Microseisms generated by super typhoon Megi in the western Pacific Ocean
MetadataShow full item record
Microseisms generated by the super typhoon Megi (13–24 October 2010) were detected on both land-based and island-based seismic stations. We applied temporal frequency spectrum analysis to investigate the temporal evolution of the microseisms. When Megi was over the deep basins of the Philippine Sea, only weak microseisms with short-period double frequency (SPDF, ∼0.20–0.40 Hz) were observed. However, after Megi traveled into the shallower waters of the South China Sea, microseisms with both long-period double frequency (LPDF, ∼0.12–0.20 Hz) and SPDF were recorded. The excitation source regions of the microseisms were analyzed using seismic waveform records and synthetic modeling in frequency domain. Results reveal that part of the LPDF microseisms were excited in coastal source regions, while the intensity of both LPDF and SPDF microseisms correlated well with the distance from seismic stations to the typhoon center. Synthetic computations of equivalent surface pressure and corresponding microseisms show that the wave-to-wave interaction induced by coastal reflection has primary effects on microseismic frequency band of ∼0.10–0.20 Hz. The coastal generation of the dispersive LPDF microseisms is also supported by the observation of ocean swells induced by Megi through the images of C-band ENVISAT-ASAR satellite during its migration process. Two source regions of the microseisms during the life span of Megi are finally distinguished: One was mainly located in the left-rear quadrant of the typhoon center that generated both LPDF and SPDF microseisms at shallow seas, while the other one was near the coasts that generated mostly LPDF microseisms.
Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 9518–9529, doi:10.1002/2017JC013310.
Suggested CitationJournal of Geophysical Research: Oceans 122 (2017): 9518–9529
Showing items related by title, author, creator and subject.
Bromirski, Peter D.; Stephen, Ralph A.; Gerstoft, Peter (John Wiley & Sons, 2013-07-25)Recent studies attribute land double-frequency (DF) microseism observations to deep water generation. Here we show that near-coastal generation is generally the dominant source region. This determination is based on ...
Bromirski, Peter D.; Duennebier, Fred K.; Stephen, Ralph A. (American Geophysical Union, 2005-04-20)The Hawaii-2 Observatory (H2O) is an excellent site for studying the source regions and propagation of microseisms since it is located far from shorelines and shallow water. During Leg 200 of the Ocean Drilling Program, ...
Coastal ocean variability off the coast of Taiwan in response to Typhoon Morakot : river forcing, atmospheric forcing, and cold dome dynamics Landry, Jennifer J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2014-09)The ocean is a complex, constantly changing, highly dynamical system. Prediction capabilities are constantly being improved in order to better understand and forecast ocean properties for applications in science, industry, ...